Transparent petroleum plastics



Feb. 11, 1941. A, P ANDERSQN 2,231,419

TRANSPARENT PETROLEUM PLASTIC l Filed Sept. 5, 1959 CPen. lndek (x) "5.0 2.0 L10 [NIP/. Clolor (s)l Flq. 1l A lnvenror: Alvin P. Ande Patented Feb. 11, 1941 *unire 2,231,419 TRANSPARENT PETROLEUM PLASTICS v Alvin P. Andersomerkeley, Calif., assignor to Shell Development Company, San Francisco, Calif., a corporation ol Delaware Application September y l s; ull. "l

It has previously been proposed to make translucent/petroleum plastics from petroleum oils by the methods set out in my Patent-2,201,466, dated May 21, 19% and the U. S. Patent 1,989,045 to Merrill and 2,029,288 to Bray. According to my Patent 2,201,466 translucent plastics may be produced from Mid-Continent (mixed base) oils which have been topped and deasphalted by extracting the oil with a naphthenic solvent to produce a ralnate and. an extract and Lredistilling the extract to produce a semi-solid or solid plastic. When Western (asphaltic base) oils are used the ramnate produced with a naphthenic solvent such as sulphur dioxide is re-extracted with a stronger naphthenic solvent such as urfural to produce a secondary extract. This secondary extract contains the desired plastic 'and may be redlstilled to the desired consistency. According to the Merrill patent translucent petroleum plastics may be produced by extracting a Western petroleum asphalt-free oil with a naphtheuic solvent and removing the lower boiling components from the extract by distillation. The plastics made by. the former process are more resistant to oxidation, have a higher penetration index and are substantially insoluble in acetone,

. while the latter' are more readily oxidized, have Va lower penetration index and are substantially soluble in equal volumes of acetone at '17 F.

30 According to the Bray patent such plastics may f be prepared by distilling a cracked material. It

further has been suggested that petroleum plastics may be made by precipitating them from their asphaltene-free solutions in petroleum oils by the use o normally gaseous hydrocarbons. One such method is set out in the patent application of Pilat and Godlewicz Serial No. '708,088 filed January 30, 1934 and another in U. S. Patent 2,143,882 to Keith.

. It is the obiect of the present invention to greatly improve the color of the heretofore known petroleum plastics.` It is a further object of this invention to increase the stability of petroleum plastics. Further objects will appear later in the specification.

It has now been found that by subjecting the previously known petroleum plastics to complete or partial hydrogenation that their color can be greatly improved, and that the plastics are ren-n dered more stable to oxidation, e. g. discoioration upon exposure to air and light as a result of the hydrogenation.

As the plastics are hydrogenated it has been observed that the penetration is raised. the amount of the increase being roughly propor- 5, 1939, Serial No. 293,339

(ci. 19e- 22) tionate to the amount of hydrogen added. However, 'the improvement in color has been found to be greatest when only a relatively small amount of hydrogen has been added, increasing degrees of hydrogenation not creating corresponding im- 5 movements in color. In general, substantially most of the improvement in color which is ob, tainable by hydrogenation may normally be achieved when the hydrogenation is less than 50% complete, and often less than 10% complete. lo Particularly susceptible to rapid color improvement are distilled petroleum plastics which rarely require more than about 30% hydrogenation for substantia color improvement.

` Frequently it is sumcient` to hydrogenate the l5 plastics to such a small extent that the reduction in the hydrogen pressure of the high pressure hydrogenation atmosphere is too small to register on ordinary pressure gauges and too small to changethe speciiic dispersion to any material 20 degree. For example, `I have found that in this manner it is entirely possible to improve markedly the color and ,color stability without materially changing most of the other characteristics of n the plastic, such as penetration, softening point, sulphur content, penetration index and solubility in furfural. The fact that the susceptibility to temperature and solubility in furfural do not substantially change shows that little actual hydrogenation takes piace. Thus the present invention may readily be distinguished from efforts on hydrogenation in the past such as are disclosed in U. S. Patent 1,949,231; in the previous work there was always a marked decrease in the temperature susceptibility of the hydrocarbons and those which were originally soluble in furfural or other naphthenic solvents became substantially insoluble in them.

The improvement secured by a small degree of bydrogenation in one phase of the instant inveni0 tion may be of great practical value. because it enables the production of very light colored,

r transparent plastics, in an inexpensive way, re-

quiring little treating reagent and causing substantially no loss, i. e., reduction, in viscous propc5 erties such as penetration and softening point.

The heretofore known albino asphallts are translucent only when spread in very thin films, thiol: films appearing a. greenish black by re- 'Elected light. To'determine their colors, they are 50 ordinarily diluted with to 1,000 parts of carbon tetrachloride or other colorless solvent and the color expressed by the A. S. T. M. color (A. S.

T. M. D-34T). However. my hydrogenated plastics are not only translucent but actually 65 genated plastic an meh in thickness. In the claims transparent is dened as representing A. S. T. M. colors of 8 or less.

Completeness of hydrogenation may be measured by reduction of the specic dispersion of the plastic. It has been shown (Industrial and Engineering Chemistry, 29, page 319, 1937) that the specic dispersion is a measure of aromaticity, very aromatic substances having speciiic dispersions in excess of 200, and paraftlns and naphthenes having specific dispersion of about 98. Therefore, an exhaustively hydrogenated albino asphalt has a speciiic dispersion of about 100 or slightly less. The approximate degree of hydrogenation actually achieved may then be expressed in per cent of the total obtainable by exhaustive hydrogenation and may be calculated by the formula wherein A=origina1 specific dispersion, and

B=speciiic dispersion of partially hydrogenated From an Edeleanu extract or a Western oil having a Saybolt Universal viscosity of 150 at 210 F., an albino asphalt was prepared by distillation, all but a few percent being taken overhead. The albino had the following characteristics:

. Original albino asphalt Specic gravity (A. S. T. M, DHL-27)---- 1.058

Solubility in acetone (equal parts by volume 77 F.) Soluble Solubility in furfural (300% at 250 F.) Soluble This material was then hydrogenated at 260- 280 C. at 200G-2500 lbs. with a Rahey nickel catalyst. Samples were taken from time to time with material. the following results:

stage 1 2 3 4 5 Degree of hydrogenatiou in percent o! total. 14 19 24 30 62 specific gravity 1. ois 1.044 1. om 1. 03o 1. 013 P 102 117 15o 17o 250+ 255 24o aso 225 16s 104 101. 5 10o 99 s4 2.4 2.4 -22 zo 4% 4% 4 3% 3% Refractive index Ngw.. 1. m57 1.6054 1. 5281 1. ma L 55m Sulphur, percent 0.07 0.68 0.48 0.35 0.15 Solubility in acetone (equal parts by volume at 77 FJ-. Soluble Soluble Soluble Soluble Soluble Solubility in iurl'ural (311% at 250 F.) Soluble Soluble Soluble Soluble Soluble Hydrogenation of. the albino asphalte may be Figure -1 is a graph showing the relationship carried out in the usual hydrogenation equipment such as an autoclave or other device capable of withstanding high temperatures and pressure and which permits intimate contact between .the catalyst, asphalt and hydrogen.

`those catalysts which are immune. or at least resistant to, sulphur such as those set out in U. S, Patents 1,932,174 to Gaus et al. and 1,932,- 186 to Pier et al. are preferred. Molybdenum sulfide has been found to be a particularly good catalyst. g

The temperature at which the hydrogenation is carried out may vary from to 450 C., partcularlygood results being obtained from 250 to 350 C. The pressure should be at least 200 lbs. per square inch and is preferably over 2000 lbs. per square inch. Y

-The following are specific examples oI'albino asphalts which were hydrogenated to diil'erent degrees, the samples being taken at different `stages of the hydrogenation and numbered l, 2, 3, etc., in the order in which they were withdrawnfirom the process. II he specic dispersion is 'given in each instance.` It should be noted that in each case the improvement in color is greatest for small changes in specific dispersion,`

and that greater changes in dispersion cause relatively smaller changes in color.

of color, softening point, 1percentage of sulphur, penetration and penetration index with the specitlc dispersion of the hydrogenated plastic at various stages of the hydrogenation. It should be noted that when the speciiic dispersion is lowered 50 points from 280 to 230 that the color changes from 9 (actually there is no such color; the'.9 is used toV designate a material too dark to give a reading) to a graph reading about 3.7 while lowering the speciic ldispersion 50 more points to 180 produces a color of 3.45; the change is less than that which can be observed with the A. S. T. M. instrument.

The color of the transparent plastics can be even further improved by distillation.' When the hydrogenated plastic from the 5th stage was subjected .to molecular distillation in which all but a few percent were taken overhead, the color improved from 3% to 2. Thus in the above ex ample by a, combination of hydrogenation and distillation the color is improved from 2 when diluted with 1000 parts of carbon tetrachloride to 2 lmdiluted.

Exnnu.: II

An acetone insoluble albino asphalt such as Ydistilled and the color of the overhead product Mid-continent oil to pmdu mi overhead ma. uct have the following characteristics:

Specific gravity 1.028 Penetration at '17 F., 100 g 59- Specific dispersion 248 softening point, "F.. 1'14 Penetration index -2.0 Color (A, S. T. M. D155-34T), (diluted with 1000 parts C014)` 3 Refractive index N,' 1.5955v Sulphur', percent 1.20.; Solubility in acetone'(equal parts) percent-- 12 This material was lhydrogenateci under the same conditions as Example 1 and produced the following results:

Stage l 2 3 Degree ofhydmgenatlon in percent of total. 29 45 58 Specific gravity at 20C l. 012 1. 004 0. 988 Pen. at 77 F. 100 8---- 118 162 243 Specific dispersion.. 205 182 162 softening point, F. 104 100. 5 94. 5 Pen. index ...V 2. 0 l. 8 l. 8 Color (A. S. T. M. lD155-34T10% in CO1.) 7+ 495+ 4% Refractive index N23"c 1.5186 1. 5635 1.5416 Solubility in acetone (equal vol. at 77 F.) 11% 9% 8% Solubility in iuriural (300% at 250 12).... 85% 70% Exmi.: III.A

A 20 penetration residual product from a similar extract to Example II had the following properties: Specic gravity at 20 C 1.032 Pen. at '17" F., 100 g-; 19 Specic dispersion 265 softening point, F 129 Pen. index v n 2.0 Color (A. S. T. M. Dl5334T-1% in C014) 5 Refractive index N25 c- 1.5989 Sulphur t 1.25% sol. in acetone (equal vol. atvl'l" F.) 8% sol. in furfural (300% at 250 F.) Soluble 'I'his material was hydrogenated-in the manner of the two foregoing examples with the following results:

Degree of hydrogenation,

Refractive index Ng" 1--- 1.5771

Sol. in acetone (equal vol.

at '17 F.) 5% 5% sol. in furfural (300% at Figure 2 shows the color.. penetration and softening points plotted against the specinc dispersion for different degreesof -hydrogenatlom To get away from the eil'ect oi' certain higlboiling materials in the residuum which tend to make the color of the plastics, all samples were plotted on Figure 2.

Exlux'rts IV Another sample of the albino asphalt'of Example I was hydrogenated using molybdenum sulfide as a catalyst. During hydrogenation the temperature was fl'om`250" to 301 C. and the pressure was from 2400 to 2700 lbs. per square inch. The following results were obtained:

Degree of hydrogenation in per solubility in furfural In the above example the actual hydrogena- `tion was very slight as is shown by the small change in specific dispersion.

Three starting materials are disclosed in the vabove examples, all* of which are classified as albino asphalts but which are derived from different starting stocks. By albino asphalt withinthe meaning of the present specification and claims is meant asphaltic petroleum products,

both naturally occurring or formed by cracking and produced by extraction and/or precipitation methods, having an A. s. T. 'M color of 31/2 or less on dilution with 1000 parts of a clear solvent and having a measurable penetration.

It is sometimes desirable to raise the penetration and penetration index of the hydrogenated' plastics. This may be done by blending the plastic with compatible synthetic resins such as methacrylic ester polymers, particularly the ethyl and higher esters, hydrocarbon polymers produced by polymerizing unsaturated hydrocarbons capable of forming polymeric homologous series, e. g. polyisobutylene, polystyrene, and other resins such as hydrogenated rubber etc.

I claim as my invention:

l. The process of improving the color of an albino asphalt comprisinghydrogenating the albino asphalt.

2. The process of improving the color of an albino asphalt comprising hydrogenating the albino asphaltl wherein the hydrogenation is less than 50% complete as calculated by the formula 10 to 30% complete as calculated by the formula wherein A the specic dispersion of the origif I nalalbino asphalt and B the specific dispersion of the partially hydrogenated albino asphalt. 4. The process of claim i wherein the albino asphalt is produced by distillation or the extract derived from a mineral oil which has been topped anddeasphalted and extracted with a naphthenic solvent.

5. The process of improving the color of an albino asphalt comprising hydrogenating the albino asphalt in the presence of a hydrogenation albino asphalt and distilling the resulting hydrogenated product to produce a light colored overhead product.

9. The process of claim 8 wherein the distillation is a molecular distillation.

l0. The process of producing a transparent petroleum plastic comprising hydrogenating an albino asphalt to an extent insuiiicient to substantially change its viscous properties, and de creasing the penetration and raising the penetration index of the resulting plastic by blending it with a hydrocarbonpolymer producedv by DDlymerizing unsaturated hydrocarbons capable of forming polymeric homologous series.

l1. The process of producing a transparent petroleum plastic comprising hydrogenating an albino asphalt to an extent insuicient to substantially change its viscous properties, and decreasing the penetration and raising the penetration index of the resulting plastic by blending it with a compatible synthetic resin.

12.v As a new product a transparent petroleum plastic comprising a hydrogenated albino asphalt.

13. As a new product a transparent'petroleum plastic susceptible to hydrogenation comprising a hydrogenated albino asphalt, the color of which cannot be substantiallyimproved by further hydrogenation.

14. As a new product a transparent petroleum plastic comprising a hydrogenated albino asphalt, the viscosity characteristics of which have not been substantially changed by hydrogenation.

15. As a new product a transparent petroleum plastic comprising a hydrcgenated albino asphalt,

the hydrogenation being less than complete as calculated from the formula A-B Y A TOX wherein A the speciiic dispersion of the original albino asphalt and B the specific dispersion of the partially hydrogenated albino asphalt.

16. As a new product a transparent petroleum plastic comprising a hydrogenated albino asphalt, the hydrogenation being from 10 to 30% complete as calculated from the formula z loX 100 wherein A the speciiic dispersion of the original albino asphalt and B the speoic dispersion of the partially hydroge'nated albino asphalt.

17. As anew composition of matter a trans parent petroleum plastic comprising a hydrogenated albino asphalt which has been distilled overhead and which has an A. S. T. M. color of about 2. y

ALVIN P. ANDERSON. 

